I finally pulled the trigger and went for a walk in these shoes on this cold Sunday morning. The current temperature is -13ยบ C, which is typical for mid January in Iowa, but I wanted to see if I could do it. I still haven't got a true measurement for the steepness of these shoes, but I am confident that the steepness is equal to or greater than 12 cm, de-rated and temperature corrected. Only electricians will get that last reference, I'm looking at you @CrushedVamp, although maybe you don't have a similar rule on the high voltage side of things, being as you don't try to stuff as many wires in a conduit as you can.
Is it early on a Sunday morning here, and I didn't meet a single person on my walk. No dog walkers, no joggers. Only one car passed me in the street. That was my plan, because although in the end, I don't think I did too bad, I didn't want anyone to see me walking in these shoes. It was a vetting process, for sure.
As usual, after about 1/4 mile, I began to find my feet. Really, a mile (1.6 km) was not too far. Maybe I'm beginning to get the hang of this. The attached photo shows circumstantial evidence that I actually did this. Also, I almost fell on my backside a couple of times, due to the dusting of snow that we got. It looks like somebody preceding me was wearing Birkenstocks, innit? How mundane.